Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The GT 226A and GT 227A are adjacent GT 220A sizes — 274 versus 324 MBH gas input, 233 versus 276 MBH output, six versus seven sections. They share R1 1/2 connections and a 7" vent, so the step is a straightforward capacity increment of about 43 MBH for roughly 86 lb more dry weight.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | De Dietrich GT 226A | De Dietrich GT 227A |
|---|---|---|
| CSA gas input | 274 MBH | 324 MBH |
| CSA output (gas-oil) | 233 MBH | 276 MBH |
| Published efficiency (as printed) | 85.2% gas (oil +3 points) | 85.2% gas (oil +3 points) |
| Cast-iron sections | 6 | 7 |
| Heating supply / return | R1 1/2 outlet / R1 1/2 return | R1 1/2 outlet / R1 1/2 return |
| Boiler vent connection | 7 in | 7 in |
| Weight (dry) | 655 lb | 741 lb |
Both models sit in the middle of the five-size GT 220A line and share the same physical connection envelope: R1 1/2 heating outlet and return and a 7" vent connection, with the same ASME IV Class 30 60 psi water rating and 230 °F maximum water temperature. The 226A has six cast-iron sections; the 227A has seven.
The printed capacity step is 274 to 324 MBH gas input and 233 to 276 MBH output, with oil input moving from 1.9 to 2.25 GPH. Dry weight rises from 655 to 741 lb. Because the connection sizes do not change between these two, the near-boiler piping plan can stay the same when one replaces the other.
As with the whole GT 220A line, efficiency is published as a single figure — 85.2% on gas, oil +3 points — not per size. The choice between the 226A and 227A should follow the calculated load and the physical space available; the 227A is the larger of the two by one section and about 50 MBH of input.
De Dietrich
The De Dietrich GT 226A is a 6-section eutectic cast-iron 3-pass commercial boiler rated 274 MBH gas input / 233 MBH output (1.9 GPH on oil) at a printed 85.2% gas efficiency (oil +3 points), with R1 1/2 supply and return connections.
De Dietrich
The De Dietrich GT 227A is a 7-section eutectic cast-iron 3-pass commercial boiler rated 324 MBH gas input / 276 MBH output (2.25 GPH on oil) at a printed 85.2% gas efficiency (oil +3 points), with R1 1/2 supply and return connections.
The GT 220A brochure prints 274 MBH input / 233 MBH output for the 226A and 324 MBH input / 276 MBH output for the 227A — one more section and about 43 MBH more output.
No. Both print R1 1/2 supply and return and a 7" vent connection.
That is a heat-loss and plant-layout decision. With identical published efficiency and connections, the deciding factor is whether the load needs the 227A's extra output.
A consultation includes a heat-loss review so the size is right the first time.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.